The major goal of this project is to evaluate a new long acting antibiotic, azithromycin, for the prevention of blinding complications and morbidity from trachoma, an inflammatory eye disease caused by Chlamydia trachomatis. Trachoma is still a major cause of infectious blindness in developing countries. Azithromycin is a new long-acting azalide closely related to erythromycin and other macrolides. Because continuing exposure and re-emergent disease are consistent features of the disease in trachoma-endemic communities, we propose to compare treatment of all persons in one (or more) villages with oral azithromycin and all persons in control villages with a topical tetracycline ointment as a means to control active infectious trachoma in children. The study will be done in three different countries where endemic trachoma is a major health problem in rural areas: Egypt, Gambia and Tanzania. This clinical trial will be the basis for the other research projects in this program project proposal: epidemiology of trachoma in the communities; molecular epidemiology of C. trachomatis eye infections in communities with endemic trachoma; and, tear antibody response in trachoma patients before and after treatment.